Cage sizes....usually the bigger the better, the one major bonus of making your own is customizing the size and shape to fit your living space.
Personally I would go wider than 2 feet, when you add a glider safe wheel it will take up a lot of space in the cage. Wheels are largeeeeeee, and need clearance all the way around it to prevent injuries.
I would go at least 3 feet wide, a brisbane cage is 2.75 feet wide and the wheel takes up half of the cage. Brisbanes are commonly used glider cages that can house up to 4 gliders, the dimensions are 63" tall (36 off stand) x 33" wide x 22" deep
The plastic mesh is just fine and glider safe. The con is it's a pain in the a$$ to clean.
The price of the hardware mesh that you posted is the average price unfortunately it is the only cheap material approved for build your own pvc cages .
You can buy pvc coated wire as mentioned it is more expensive but on the other hand it will last way longer too.
That's the other draw back to making your own, in the end it costs just as much or maybe more than a regular pre made cage.